Background: Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography (FDG-PET/CT) functional imaging has shown to be an invaluable non-invasive, diagnostic method, enhancing the accuracy in the presenting of Non-Small Cell Lung Cancer (NSCLC). The purpose of this research was to evaluate the role of the maximum standardized uptake value (SUV max) in PET-CT in staging and follow-up of operable and non-operable patients with NSCLC. Methods: This prospective research carried on 50 cases with histopathological diagnosis of NSCLC were mentioned to do PET/CT scanning for initial staging of the disease (17 patients died, 28 survived, and five were lost to follow-up so 28 patients out of 50 came for follow-up after treatment with surgery, radiotherapy, or chemotherapy). All cases underwent intravenous contrast media, 18F-FDG Dosage Administration, CT Technique, PET Technique, PET-CT Fusion, and PET/CT Interpretation. Results: SUV max is a semi-quantitative technique of determining 18F-FDG uptake by tumor cells. Adenocarcinomas have lower 18F-FDG uptake and lower SUV max measurements compared to the squamous cell carcinoma. The average SUVs of tumours ≥ 4 were significant increased compared to those < 4, and additional analysis showed that SUV max was significantly correlated with tumor size. SUV max is a prognostic factor of T and N stages as T1 lesions had a decrease average SUV max compared to T2 and a lower mean SUV max than T3/T4 lesions, also we found that the mean SUV max of N0 is lower compared to that of NI, NII, and lower than NIII. There was a strong association among ΔSUV and Δ size. Conclusion: FDG-PET/CT was a valuable, efficient, and reliable method of analysis in the initial staging and follow-up of lung cancer cases, and lately became a portion of the international standards in the diagnosis and the follow-up of cases with bronchogenic carcinoma.